Zelda announced she was quitting Twitter and Instagram in August after Internet trolls taunted her about her late father, reported the Huffington Post.
"I just want to say thank you for all the stories and letters I've been receiving, especially from those who've also lost loved ones," she tweeted.
"I don't come online often, but reading of others who have dealt with this loss and gone on to live happy, full lives is helpful. Truly," she added.
Williams also retweeted an adorable photo of her father.